Monomeric HIV-1 gp120 exterior envelope glycoproteins have failed to efficiently elicit neutralizing antibodies. We have therefore attempted to reconstitute the trimeric native g120 structure as solid phase proteoliposomes (PLs) containing HIV envelope glycoproteins (EnvPLs). This study characterizes the native trimeric structure of the glycoproteins in a lipid bilayer environment and will test them as immunogens.[unreadable] [unreadable] We will also reconstitute the 7-membrane spanning HIV-1 co-receptor molecules (CCR5 or CXCR4) in solid phase liposomes and assess their function to bind chemokine or HIV-1 gp120-CD4 complexes. We will also develop both a Biacore assay and a lipid-reconsituted ELISA (L-ELISA) to test binding of ligands to the co-receptor molecules.